Manufacture of purified soda-pine pulp.



WILLIAM H. SHARP, OF PHILADELPHIA,J/PENNSYLVANIA.

MANUFACTURE OF PU RIFIED SODA -PINE PULP- Specification of LettersPatent.

. Patented Jan. 15, 1907.

Application filed November 6, 1908. Serial No; 342.172.

it whom it may concern: I

Be it known that 1, WILLIAM H. SHARP, residing at No. 1813 Chestnutstreet, in the. city of Philadelphia, county of Philadelphia, and Stateof Pennsylvania, have invented a certain. new and useful Im i'ovement inthe bianuiaoture of Purified ode-Pine Pulp, whereof the followin is aspecification.

As indicated in the above statement, my process is limited to themanufacture or the pulp or cellulose from pine-wood as distin-r guishedfrom other kinds of 'wood, and it. is also limited to the so-called sodaprocess, whereby the wood is primarily digested.

Without attem ting to indicate all the varieties of pine w ose similarcharacteristics render them amenable to treatment by my process, thefollowing may be stated as typical ofsuch varieties, the commercial namein each instance being stated as most 'ob viously d'escriptive-viz.,short-leaf sprhcepine, loblolly-pine, ioxtail pine, long leaf pine,old-field pine, jack-pine, :ci ger-prneL When the soda process is empoyed upon pine-wood of this character, it is found that at theconclusion of the process there are re-- sidual substances which resistthe urifying reagents and which discolor the pu to the seriousimpairment of its commercial value. These substances do not yield tc'thebleaching agent usually cm loyed-viz., ordinary bleaching-powder orclilorid of limebut are extremely persistent; and the object of mypresent invention is I substances so that they shall no longer imtoremove or modify the To this end I conduct the process as follows: Thepine-wood in the form oi chips or small fragments is first digested witha solution of caustic soda of the pair the product.

strength of ab0ut 12 to 13 .Baum for about ten hours at a pressure ofabout one hundred and twenty pounds. It is then thoroughly washed withwater, and after washing it is treated with bleaching-powder of chloridof lime, about twenty pounds of this reagent being used to each onehundred pounds of the washed pulp. After the action. of theblcaching-pmvder is nearly exhausted I. add about five pounds of apermanganate salt, preferably permanganate of potash or permanganate ofsoda, to one ton of the pulp. The mass is then stirredsigned my name, atPhiladel thoroughl and as soon as the color indicates that the csiredreactions are obtained it is washed with a dilute solution of sulfurousacid until all the soluble traces of the manganous compounds have beenremoved. The

pulp is then ready for use in the ordinary manner.

Having wish it to thus described my invention, I be unde'rstood that Ido not claim, broadly, the use of a ermanganate in connection with thebleac in of pul for I am aware that in the so-ca led sulf ite .processfor the manufacture of ulp permanganate has been used. Its use, owever,so far as am aware, has been at a difierent stage of the process and ineatly larger percentages than the one which I employ. The sodaprocess,'to which my invention 1s limited,-presents entirely differentconditions at that stage in which I'emplo the permanganate, and althoughthe de ective character of the ulti-- mate'product of the soda processin the particulars above named has long been known and the desirabilityof a remedy therefor has been fully a preciated, it has not, so far as Iam aware, een deemed possible to obviate the difficulties. of noveltyupon the discovery that where pins-wood is subjected to treatment by theso-call ed soda process the reactions which occur and the resultantcondition of the product which is attained after the usual leachingstage has been completed are such I therefore base my claim as to permitthe successful use of a relatively small amount of permanganate forremoving the last and persistent traces of discoloring material.

I claim I The hereinbefore described.process of man uiacturingsodainepulp, which consists in, first, digesting thepine-wood with acaustic soda; second, washin third, treating with chlorid of lime; fourttreating with a ermanganate; and, finally, washing in a di ute sulfurousacid, substantiall as set forth.

In testimony whereof have hereunto hia, Pennsylvania, this 5th day ofNovem er, 1906.

, WILLIAM H. SHARP. -Wi-tnesses:

JAMES H. BELL, E. L. FULLERTON

